Anyone know where I can find a some diagrams of coolant flow/direction?

I plan to put H89 head and stock manifold onto an A12 block.

I have noticed between my A12s they have different pipes pressed into the block. I assume for different manifolds etc.

I'm guessing the front pipe goes to the radiator and also heater, the rear pipe goes to the mainfold and on the A12 head the fitting at the back of the head goes to the heater.

What about the H89 head which doesn't have a pipe/fitting to go to the heater and instead a temp sensor? Has someone put the sensor in there when it shouldn't be?

The pipe at the back end of the block is the crankcase breather.
Dont put coolant into it !

My H89 head had a fitting for a heater but it had been crimped shut. I think by the factory as i have seen others done in exactly the same way.
Heaters not required in Thailand..

The front pipe is the Suction Pipe, it pulls coolant from the radiator.

Some Suction Pipes have one or two small fittings
* heater return (B110s have this built into the lower radiator hose)
* water-heated manifold return

H89 head is identical to the A12 head as far as coolant flow and heater. The only fitting either have for the heater is the rear tap. The rear heater tap can be plugged, with no ill effect on the cooling system

Here's the Factory Service Manual coolant flow diagram for standard B110

Note the suction pipe is the simple one (no small fittings), and the heater returns to the lower radiator hose Tee







Here's the 1980-1985 Datsun 1200 with heater return in the Pipe

Here is the H89 manifold water return. These were used with 2-fitting Suction Pipes (1 for the heater return, 1 for the manifold return)

Arrow pointing to the water return

Attach file:

---

  B310 A14 inmani bottom.jpg (48.20 KB)


  B310 A14 inmani ports.jpg (29.43 KB)


  B310 A14 inmani top.jpg (36.48 KB)

Thanks for all that ddgonzal.

So am I right to say the temp sensor in the back of my H89 head should be a fitting and supply the heater?

What about the pipe on the side of the block to the rear? Where does that go to?

Just worked it out :)

Never seen a temp switch in the back of the cylinder head, in any case you can unscrew it and reconnect the heater hose

Some heads had a temp switch on the manifold side at the rear for emission controls

For a temp gauge you can fit the sender anywhere on the head it will fit

For a thermo fan, the switch should be fitted outside the head either in the radiator or radiator hose